One type of fluid ejection device is an inkjet-printing device. An inkjet printing device forms images on media by ejecting fluid such as ink though an orifice in fluid communication with a firing chamber. In some examples, droplets of fluid are thermally ejected from the inkjet-printing device using a heating resistor. When electrical power is applied to the heating resistor, resistance of the heating resistor causes the heating resistor to increase in temperature. This increase in temperature causes a bubble to be formed in the firing chamber, which results in ejection of a droplet of fluid through the orifice.